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This paper details petrological and geochemical studies of an ultramafic–mafic intrusion in the Southern Eastern Desert of Egypt. The Dahanib complex shows a concentric zonation, from dunites at the core, through chromitites, clinopyroxene-rich dunites, wehrlites, harzburgites, gabbronorites and layered gabbros, to hornblende gabbros/diorites at the rim, similar to other Alaskan-type complexes. These...
The Kumta and Mercara suture zones welding together Archean crustal blocks in western peninsular India offer critical insights into Precambrian continental juxtapositions and the crustal evolution of eastern Gondwana. Here we present the results from an integrated study of the structure, geology, petrology, mineral chemistry, metamorphic P–T conditions, zircon U–Pb ages and Lu–Hf isotopes of metasedimentary...
The South China Block, composed of the Yangtze and Cathaysia sub-blocks which were sutured along the Jiangnan Orogen, preserves the records of multiple tectonothermal and metallogenic events coeval with global supercontinental cycles. In this study, we attempt to evaluate the mantle dynamics in this region based on P-wave tomographic analyses from data recorded by the China seismic network from 2007...
The Makkah quadrangle is a part of the Jeddah terrane in the Precambrian basement, Western Arabian Shield of Saudi Arabia. Gabal Taftafan mafic–ultramafic complex lies within the central part of the Makkah quadrangle. The Taftafan mafic–ultramafic complex is a well-differentiated rock association which comprises of dunite core, hornblende- and plagioclase-bearing peridotites, troctolite, clinopyroxenite...
Reaction products between hydrothermal fluids and uppermost mantle harzburgite-lowermost crustal gabbro have been reported along Wadi Fizh, northern Oman ophiolite. They are named mantle diopsidite (MD) or crustal diopsidite (CD) depending on the stratigraphic level. They construct network-like dikes crosscutting structures of the surrounding harzburgite or gabbro. The MD is mainly composed of diopsidic...
Metamorphic regimes in Archean terranes provide important keys to the plate tectonic processes in early Earth. The North China Craton (NCC) is one of the ancient continental nuclei in Asia and recent models propose that the cratonic architecture was built through the assembly of several Archean microcontinental blocks into larger crustal blocks. Here we investigate garnet- and pyroxene-bearing granulite...
The Cuddapah basin (CB) is one of a series of Proterozoic basins that overlie the Archaean cratons of India, and contains a unique stratiform carbonate-hosted uranium mineralisation. In the present work, we discuss stable (C, O) and radiogenic (Nd, Sr) isotope systematics of carbonates of the Papaghni sub-basin in order to understand uranium ore forming processes and geodynamic evolution of the CB...
Late Precambrian intrusive rocks in the Arabian–Nubian Shield emplaced within and around the Najd Fault System of Saudi Arabia feature a great compositional diversity and a variety of degrees of deformation (i.e. pre-shearing deformed, sheared mylonitized, and post-shearing undeformed) that allows placing them into a relative time order. It is shown here that the degree of deformation is related to...
High-grade para- and orthogneissic rocks near the Chilka Lake granulite complex, northern part of the Eastern Ghats Belt show complex structural and petrological history. Based on field and petrographic characters, five (M1–M5) metamorphic events could be identified. The earliest metamorphic event (M1) produced amphibolite grade mineral assemblage which produced the peak granulite (M2) assemblages...
The Lützow–Holm Complex (LHC) of East Antarctica forms part of the Neoproterozoic–Cambrian high-grade metamorphic segment of the East African–Antarctic Orogen. Here we present new petrological, geochemical, and zircon U–Pb and Lu–Hf isotopic data for meta-igneous rocks including charnockite, felsic gneiss, metagabbro, and mafic granulite from the LHC and evaluate the Neoarchean to Early Paleoproterozoic...
The southeastern sector of the Hafafit Metamorphic Complex, southern Eastern Desert of Egypt comprises infrastructural orthogneisses of tonalite and syenogranite parentage, amphibolites, and a volcano-sedimentary association. These are overthrust by an obducted suprastructural ophiolite nappes via the Nugrus thrust. The protolith of the biotite–hornblende-gneisses was formed during island-arc accretion,...
Accretion along continental or island arcs at cratonic margins was responsible for most Paleoproterozoic crustal growth. For the development of the Krishna orogen, India, at the southeastern margin of the Eastern Dharwar craton (EDC), two contrasting models, one by long-lived accretion between ~1.85Ga and 1.33Ga terminating in continental collision with the Napier Complex and the other involving continental...
The Gerf ophiolite is the largest mantle-derived complex in the Arabian–Nubian Shield (ANS). This ophiolitic complex extends for tens of kilometers in the south Eastern Desert (SED) of Egypt as part of the Allaqi–Heiani and Oneib-Sol Hamed suture zones. The ultramafic section of the Gerf ophiolite comprises serpentinites, serpentinized peridotites and minor pyroxenites. All rocks contain relics of...
Geological mapping and P–T path reconstructions are combined with monazite chemical age and Secondary Ion Mass Spectrometric (SIMS) U–Pb zircon age determinations to identify crustal domains with distinctive evolutionary histories in the Rengali orogen sandwiched between two Grenvillian-age metamorphic belts, i.e. the Eastern Ghats Granulite Belt (EGGB) in the south, and the amphibolite facies Gangpur...
The Nilgiri Block is one of the major Archean crustal blocks that define the tectonic framework of southern India. Here we report geologic, petrologic, geochemical, and zircon U–Pb, –REE, and –Lu–Hf data of a highly metamorphosed and disrupted sequence of amphibolite, meta-gabbro, websterite, volcanic tuff, meta-sediment, and banded iron formation (BIF) from the northern fringe of the Nilgiri Block...
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